Washington's restaurant workers' union has served up a putrid dessert that threatens to spoil the victory celebration of a successful labor and management effort to save the District of Columbia's bankrupt unemployment compensation program.

The City Council six weeks ago passed a new jobless benefits program that was developed after months of awkward and unprecedented cooperation between the Greater Washington Board of Trade and the Metropolitan Washington Council AFL-CIO.

Never before have the city's principal labor and business groups endorsed a joint solution to a problem on which they fundamentally disagree. It was not an easy compromise.

Labor leaders had to swallow hard and agree to give up eight weeks of jobless benefits at a time when the unemployment rate is lingering at near-record levels and long-term unemployment is becoming agonizingly common. The plan reduces the maximum time that unemployed D.C. workers can collect benefits from 34 to 26 weeks, the same as Maryland, Virginia and most other states.

Business leaders had to accept sharp increases in D.C. unemployment taxes to raise the $240 million needed in the next three years to restore the benefit fund to solvency. Much of the additional taxes will be paid by employers who have traditionally had stable employment and therefore low unemployment taxes; in some cases, the minimum tax they pay will jump from $7.50 per worker to $64.

D.C. jobless benefits will remain among the highest in the nation--up to $206 a week--compared with $138 in Virginia and Maryland's soon-to-be-raised $153.

Along with the short-term concessions by both sides, the D.C. jobless bailout bill created a nine-member commission that will seek long-term solutions to the District's unemployment compensation problems. The panel picked by Charlene Drew Jarvis, who chairs the council's committee on housing and economic development, will meet for the first time later this month to begin work on a new jobless benefits package to take effect in 1985.

Both the Board of Trade and central labor body have expressed reservations about the unemployment benefits compromise, voicing rhetorical concerns clearly meant to placate objectors in their own ranks.

But just when the two sides and the council ought to be enjoying a victory banquet, in comes Local 25 of the Hotel and Restaurant Employees Union and the local Food and Allied Trades Council. Led by restaurant union secretary-treasurer Ron Richardson, the groups are launching a campaign to throw out the jobless benefits reform package.

"It's time the City Council started worrying about the people of the city, and not just the business interests," argues Richardson, one of Washington's most outspoken and aggressive labor leaders. Richardson has made a name for himself with unusual organizing tactics; instead of trying to sign up a restaurant's workers to be union members, he hires pickets to pressure the restaurateur to sign a union contract.

The fiesty spokesman for the city's waitresses, busboys, maids, dishwashers, janitors and room clerks got his local thrown out of the Metropolitan Washington Council of Unions last year. Officially, the dispute was over paying dues to the central body, but underneath that was an intra-labor political struggle that apparently is still going on.

Richardson's opponents will tell you that his own political agenda and his antagonism toward the central labor body are behind the opposition to the jobless plans.

Be that as it may, the hotel and restaurant workers are among the Washington employes most likely to find themselves out of work. Their work is seasonal, the pay is low and restaurants fail all too often to give Local 25 members much job security. They need good unemployment benefits as badly as anyone in town and will certainly suffer from cutting the benefit period to 26 weeks.

What's disturbing about the objections, however, is that they are coming after everybody else involved has settled their differences and from a group that said nothing during the entire decision-making process. Richardson's group wants D.C. voters to petition for "more generous" jobless benefits, but has offered no specifics.

What the months of wrangling between labor and business demonstrated is that there is simply no way to maintain jobless benefits at their present level at a time when the benefit fund is almost $60 million in debt. That lesson has been all but ignored by the belated opponents.

The agreement to simultaneously cut benefits and raise taxes also reflects a growing realization that there are limits on how far the District--or anyone else--can deviate from the realities of the marketplace.

No local government, no industry, no union can maintain for long a standard of living, a pay scale or a jobless benefit package that is radically different from the rest of the world. The United Auto Workers of Michigan and the Steel Workers of Pennsylvania and Ohio became some of the world's highest paid workers only to lose their jobs to Japanese competitors working for lower wages. Northern industrial states decided they were not vulnerable to cut-rate competition and the Sunbelt was born. The D.C. government offered deservedly generous benefits to the jobless, only to find that the taxes to support those benefits were driving employers out of the city.

The District doesn't have to underbid the niggardly unemployment benefits paid by Virginia in order to attract business and jobs. But neither can it afford a system so costly that local employers cannot compete for jobs with Maryland.

The District's latest unemployment benefit reforms manage to balance the social conscience that demands generosity for the jobless with the mandate of the marketplace to remain competitive. The plan worked out by the council in cooperation with business and labor leaders is a fair one. Let's leave it alone and let it work.